The present invention relates generally to chewing gum compositions, and particularly to chewing gum compositions capable of being prepared with prolonged flavor release.
Most chewing gum compositions contain a generally water-insoluble gum base, water-soluble sweeteners that are either natural or artificial, and a flavoring that may be added in a variety of forms. Also, the gum may contain various additives such as plasticizers, softeners and bulking agents to improve consistency and to enhance the chewing experience.
A commonly noted deficiency in chewing gums remains the relatively rapid exhaustion of the flavor sensation during chewing. This deficiency is most pronounced in the instance of chewing gums, as flavor loss frequently occurs within 5 to 7 minutes after chewing commences, and the flavor taste is further reduced thereafter. One of the causes of this loss is the general tendency for the bolus to retain large percentages of the flavor even during mastication. Thus for example, an average of 50-70% of the flavor ingredient added to a given gum composition during its formulation may remain trapped in the spent gum base.
Efforts to compensate for this reduced flavor sensation have included the addition of higher than normal amounts of flavor or sweetener to the formulation, and the preparation and use of flavors having controlled water solubility or other release characteristics, or the addition of sweeteners to extend the flavor sensation. None of the approaches broadly recited above and specifically referenced hereinbelow have succeeded in appreciably extending flavor release.
Generally, the flavor component regardless of how added to the gum composition is entrapped and retained by gum base ingredients. This entrapment renders the flavor unavailable as discussed above. High base chewing gum compositions generally render a hard chew and are apt to retain more flavor than lower base-containing compositions, thereby having less available for release during chew.
Efforts to arrest flavor entrapment in the gum base turned to encapsulation. Accordingly, flavors were encapsulated in many of the same ingredients in the gum base toward which the flavors have exhibited affinity, such as the resin, elastomer and vinyl polymer components, as well as other suitable film formers and similar agents. The encapsulated flavors still suffer from the drawbacks and deficiencies of the prior art however, as a large quantity of the flavor is still retained by the base, and the release of the flavor from the encapsulating matrix is frequently incomplete.
A full discussion of the prior art with respect to the extension of flavor is found in U.S. Pat. No. 4,590,075 to Wei et al., the disclosure of which is incorporated by reference. More particularly, the patentees discuss the preparation of encapsulated flavors which are added together with a quantity of a non-confined hydrophobic flavor oil to a suspension agent before formulation in a chewing gum (U.S. Pat. No. 3,920,849 to Marmo et al.); the encapsulation of flavor in high molecular weight material such as polyvinyl acetate (U.S. Pat. No. 3,826,847 to Ogawa et al.); the preparation of a flavor composite by crosslinking the flavor with a water-insoluble hydrophilic polymer such as hydroxyethyl acrylate (U.S. Pat. No. 3,761,286); the preparation of microencapsulated flavor particles and their dispersion in a slurry on the surface of a chewing gum (U.S. Pat. No. 3,962,463). Further, U.S. Pat. No. 4,695,463 to Yang et al. is noted and discloses a flavor delivery system that relies on the immobilization of the flavor within a crosslinked hydrocolloid multivalent alginate or carageenenate matrix.
One exception to the adoption of flavor fixation is found in U.S. Pat. No. 4,157,401 to Stroz, et al., where a limonene derivative was introduced in combination with a quantity of unfixed flavor, on the basis that the limonene prevents the migration of the flavor to the water-soluble phase of the gum and resultingly, toward its premature release. This patent confirms the shortcomings of the use of unfixed flavor that were perceived in the art from the time of the patent forward to the present.
In view of the foregoing, a need therefore exists for the development of improved chewing gums particularly having high base content that are capable of offering extended flavor sensation in combination with improved shelf stability.